Pity the poor woman who yesterday opened a Tesco's bag of spinach only to find a dead frog lurking in the contents. It seems she had a made a nice spinach salad for two and halfway through eating it her dining companion had found the unfortunate amphibian by piercing it with a fork. "My friend was sick several times as she is a vegetarian," she said, but surely even the most enthusiastic omnivore would have been wrong-footed by the discovery. Properly prepared and cooked, of course, the right kind of frog can just about hit the spot, but finding a dead one flopping out of a bag of spinach is no way to whet the appetite.

Of course, we may not be hugely surprised to find the occasional aphid in a bagged salad particularly if it's organic, and some may even view that as a good thing. But larger animals are a different matter. So how exactly does a frog get into a bag of leaves? Perhaps what we have here is less a case of roaming amphibians and more a case of salad-bag sabotage in a world of bitter rivalry and sharp practice among supermarket middle-management.

A mouse in a loaf of Hovis Best of Both bread. Photograph: Cherwell District Council/PA

This may sound far-fetched, but according to a rather pissed off sounding bakery executive it may actually have been the case in one incident of food horrors lurking in packaging. Three years ago Word of Mouth was up in arms about the strange case of the mouse in maltloaf, a story which has a whimsical, almost fairy-tale feel to it until you look at the photograph which is simply grotesque. The bakery's managing director attributed the presence of the mouse to sabotage, which is so bizarre and macabre I am considering crafting a thriller around it.

It seems too that frogs are just the tip of the iceberg lettuce when it comes to unsavoury surprises festering in our shopping. Word of Mouthers have revealed a whole smorgasbord of delights found lurking in their food – trifling delicacies such as preserved caterpillars in tinned pears, dead tropical bugs in tea, mice in milk, a single gammy tooth in a bag of frozen prawns, slugs in iceberg lettuce, condoms in tinned peas, maggots in chocolate bars, wasps in crisps, floor cloths in wild mushroom soup, eyeballs in sausage – the list goes bafflingly on.

So what has Tesco's got to say about the frog in spinach thing? Not a lot. The press officer I spoke to was rather cagey, trotting out the usual line "We are not sure what happened but are investigating the matter thoroughly" before throwing in a loaded "we are speaking to our suppliers", which sounded suspiciously like trying to shift the blame to me.

Anyway, no worries because food victims normally get a handsome pay-off, right? Well, not exactly. Mousey bread man was paid a handsome £17,000 in compensation, but apparently frog spinach lady got just £10 in Tesco gift vouchers for her trauma, while one lucky Guardian commentator claims to have been granted a £5 voucher for a bad experience involving a battered sausage and a razor blade. Small recompense indeed.